It's often said by laymen that the UK's weather is unique. But what makes it so different from anywhere else?

Whatever you think of the British weather, if you don't like it one day there's always a good chance you might like it the next.

Weather, in meteorological terms, refers to the daily elements like temperature, wind and rain. And in Britain they can all change hour by hour and day by day.

It's this diversity and changeability that makes British weather so distinct, say meteorologists. While temperatures are fairly mild and there are four distinct seasons, you can also get warm weather in the middle of February and freezing rain in the middle of August - or both in one day.

"Other countries might have more dramatic weather," says Dr Liz Bentley, head of the Weather Club at the Royal Meteorological Society. "In India and Pakistan you get monsoon season, but you can usually predict the day it will start and the day it will finish.

Find out more

The Great British Year depicts the changes of the land from each season to the next. Watch episode two at 21:00 BST on Wednesday 9 October on BBC One.

"In the UK you sometimes have to look at the weather forecast several times in one morning just to plan a trip out that afternoon. Things can change that quickly."

Many meteorologists call the British weather unique, although some say you could argue the weather in all countries is unique because no two are the same geographically and geologically. But they agree it is hard to find another country in the world with weather that compares to the UK.

So what makes it so distinctly variable?

"Britain's unique weather is all down to the fact it is an island and where it's positioned on the planet, between the Atlantic Ocean and a large land mass, continental Europe," says Helen Chivers from the Met Office. "There is a lot going on meteorologically where we are."

Britain is under an area where five main air masses meet. An air mass is a large body of air that has similar temperature and moisture properties throughout.

In the UK they are either polar or tropical, depending on where the air mass originated; they are also divided into maritime or continental, depending on whether the air has passed over land or sea.

They come from all directions and can bring all types of weather.

When they meet it creates a weather front. The air masses fight it out and the one that wins dictates the weather. The bigger the difference the worse the weather can be. There is a sixth air mass, the returning Polar Maritime, which is a variation of the Polar Maritime.

One more important thing to throw into the mix is the jet stream. It is a high-altitude ribbon of fast-moving air that is associated with weather systems in the UK. The position of the jet stream can make a huge difference to the type of weather we experience.

All in all, it's quite an extraordinary mix of atmospheric conditions battling it out.

"It's what makes the British weather so fascinating," says Bentley. "Experiencing such big changes so quickly is unique."

Fascinating or frustrating, the layman might argue, but no other country in the world gets the same weather, say experts.

The British year in pictures

"Japan is probably the only other place that has similarities to the UK when it comes to weather," says Chivers.

"It is similar to us but in reverse. It is an island and has the Pacific Ocean to the east and Eurasian continent to the west. Britain's variations in weather really are that rare."

These variations pose problems, from when to have a barbecue to effective planning for businesses. Companies spend millions trying not to be caught out by the British weather.

"From energy companies, supermarkets and insurance firms to banks, technology companies and local authorities, they all need to plan for the weather," says Richard Tipper, director of Ecometrica, which works with companies to get the climate and weather data they need to plan efficiently.

"It's the amazing changeability in British weather that is unique. It also means planning for it isn't always easy."

Subtle changes in the weather are happening and will continue, says Bentley.

"We are starting to see more record-breaking weather, record droughts and record rainfall," she says.

More from BBC Nature

Last year is a good example. The dramatic switch from drought in early 2012 to the wettest April to June on record was of a magnitude never seen before, according to the Centre for Ecology & Hydrology (CEH).

Hosepipe bans were brought in early in the year but by early autumn levels of groundwater were "well above" average.

But the country's fascination with the weather probably won't change. Nor will some people's love for it.

"There is a real beauty about the weather in the UK," says Bentley.

"You might be guaranteed sun in other countries but constant sunshine can get dull. People move to other countries but often they end up missing the British weather and the seasons.

"There are also some real upsides. When we get unexpected sunshine in the UK everyone's day is better. It just feels like we are getting a special treat and we are so much happier."

The Great British Year is on BBC One at 21:00 BST on Wednesday 9 October or catch up with iPlayer.